> -----Original Message-----
> From: Jo Hornsby [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, February 28, 2001 4:18 AM
> To: C. X. Lu; [EMAIL PROTECTED]
> Subject: RE: [Sip-implementors] Question about how SIP uses TCP or UDP
>
>
> > In rfc2543bis-02.ps (p75) it says
> >
> > "If a server needs to return a response to a client and no longer
> > has a connection open to that client, it MAY open a connection to
> > the address listed in the Via header. Thus, a proxy or user agent
> > MUST be prepared to receive both requests and responses on a
> > "passive" connection"."
> >
> > And on P59 it says:
> >
> > "The client originating the request MUST insert into the request a
> > Via field containing the transport protocol used to send the
> > message, the client's host name or network address and, if not the
> > default port number, the port number at which it wishes to receive
> > responses. (Note that this port number can differ from the UDP
> > source port number of the request)."
> >
> > Combining these two statements, can we get the conclusion that the
> > Draft is requiring UAC to be repared to receive reponses not only on
> > the TCP connection
>
> (If you mean the TCP connection over which the request was sent,
> yes.)
>
> > (in UDP case it will be the connect socket)
>
> It's unlikely to be the connected UDP socket, unless you connected
> the socket that is also listening on 5060 (or whatever your main
> port is).
>
> > but
> > also on the listening ports of UAS(C?) (in the UDP case, it will be
> > a non-connect socket)?
>
> Very much so.
>
> > So even a response coming from a different IP
> > address, the UAC SHOULD be able to receive it according to the
> > Draft/RFC?? Does the Draft/RFC madate this implementation?
>
> The draft is silent on this issue, thus I guess you have to
> be prepared for the source address to be different from what
> you might expect.
Definitely. "the port number it wishes to receive responses on" seems pretty
clear to me that you should be prepared to receive messages on that port.
Nothing in the spec says that those are restricted to coming from a specific
address.
-Jonathan R.
---
Jonathan D. Rosenberg 72 Eagle Rock Ave.
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.cs.columbia.edu/~jdrosen PHONE: (973) 952-5000
http://www.dynamicsoft.com
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